Question: Solve for $x$ and $y$ using substitution. ${6x-y = 4}$ ${y = 5x-3}$
Explanation: Since $y$ has already been solved for, substitute $5x-3$ for $y$ in the first equation. ${6x - }{(5x-3)}{= 4}$ Simplify and solve for $x$ $6x-5x + 3 = 4$ $x+3 = 4$ $x+3{-3} = 4{-3}$ ${x = 1}$ Now that you know ${x = 1}$ , plug it back into $\thinspace {y = 5x-3}\thinspace$ to find $y$ ${y = 5}{(1)}{ - 3}$ $y = 5 - 3$ $y = 2$ You can also plug ${x = 1}$ into $\thinspace {6x-y = 4}\thinspace$ and get the same answer for $y$ : ${6}{(1)}{ - y = 4}$ ${y = 2}$